With the advent of external devices such as printers, scales, and interfaces to computers in communication with electronic postage meters, it has become possible to offer meter customers a large number of optional features not possible or feasible with the meter alone. Each additional feature, however, creates a larger number of possible combinations of features. Therefore, in order for the meter company to provide a large selection of features and feature sets, it may pursue one of the following approaches:
In a first approach, the meter company may maintain a large inventory of external devices which have the various features. Although this approach has strong security, it is costly and inefficient. Furthermore, a customer wanting to change the set of features on his external devices must wait for an agent of the company to provide external devices having the desired feature set. If the agent does not have a large inventory, it becomes necessary to have external devices with the desired feature sets shipped from or built at the factory. Therefore, any attempts to reduce the number of external devices in stock will adversely affect the length of time necessary to service the customer's request.
In a second approach, the meter company may provide external devices that include all the desired features, but are disabled in some manner. Although this approach provides great flexibility, it does not provide much security. A customer may easily be able to enable unauthorized features himself by inspecting and manipulating the devices or by observing an agent enabling or disabling the desired features. Furthermore, an agent may enable the desired features without notifying the company. As a result, the company may have a large amount of lost profits due to unauthorized feature use.